1. Field of the Invention
The present invention relates to a medical solution delivery system and, more particularly, a system suitable for continuously delivering a medical solution to a blood vessel, extraduramater, subcutaneous tissue, or the bladder of a patient at a well-controlled flow rate.
2. Description of the Prior Art
In order to administer a very small amount of a medical solution such as a antibiotic agent, or carcinostatic agent, or the like to the blood vessel, bladder, or the like of a patient, there have been proposed various kinds of medical solution delivery systems comprising an expanded balloon of an elastic material with a medical solution filled therein, a housing for holding the balloon therein, and a flow control means connected to the balloon to control a flow rate of the solution, as disclosed in JP-A- S50-108790, JP-A- S56-102252, JP-A- H1-135360 and JP-A- H3-170163. In such a system, the medical solution is delivered from the balloon little by little by means of shrinkage thereof. In other words, the balloon is used as a container for storing a medical solution and as a motive power source for delivering the solution therefrom.
Accordingly, it is inevitable with such a medical solution delivery system to avoid influences of a material used for production of the balloon. The balloon is made of an elastomeric gum rubber, the force applied to the medical solution varies with time during injection, thus making it impossible to delivery the medical solution at the accurately controlled flow rate. In addition, it is required to use an elastomeric gum rubber having no problem caused by eluants.